Triglyceride–water emulsions stabilised by starch-based nanoparticles

Abstract

Emulsions stabilized solely by edible particles have attracted great interest very recently because of their potential application in the food and pharmaceutical fields. In this work, starch-based nanospheres are used as the particulate emulsifier for triglyceride–water emulsions. The effects of particle concentration, oil:water ratio and salt concentration on emulsion type and stability are investigated in detail. The linear relationship between the inverse average oil drop diameter and the particle concentration allows estimation of the coverage by particles of the curved oil–water interfaces. Confocal microscopy confirms that the nanospheres are mainly adsorbed at the liquid interface to form a dense film around the dispersed drops impeding coalescence. Moreover, catastrophic phase inversion from oil-in-water (O/W) to water-in-oil (W/O) emulsions is achieved by increasing the volume fraction of oil beyond 0.65. The stability to creaming of O/W emulsions increases approaching phase inversion, as does the stability to sedimentation of W/O emulsions. Finally, O/W emulsions are destabilized with respect to coalescence on adding salt.